Pyrotechnic devices

ABSTRACT

Primers comprising a deformable tube, lengthwise anvil therein and primer composition between tube and anvil are used for igniting pyrotechnic compositions such as propellants having a solid oxidising agent. The use of such primers which were previously only used as part of photographic flash bulbs gives considerable advantages.

United States Patent Murray et al.

Oct. 14, 1975 PYROTECHNIC DEVICES lnventors: Dudley Charles Murray,Salisbury;

William Rupert Brooke Elstow, Laverstock, both of England Assignee:Pains-Wessex Limited, Salisbury,

England Filed: July 27, 1973 Appl. No.1 383,109

Foreign Application Priority Data Aug. 1, 1972 United Kingdom 35969/72US. Cl. 102/86.5; 102/32; 102/45; 102/70 R Int. Cl. F42C 19/08; F42B4/02 Field of Search 102/45, 86.5, 34.4, 70, 102/32 References CitedUNITED STATES PATENTS 11/1964 Root 102/45 7/1919 Asbury l02/85.6

2,519,123 8/1950 Dwyer et a1. l02/34.4 X

2,818,811 1/1958 Kempler 102/45 3,046,891 7/1962 Treat, Jr. 102/453,457,860 7/1969 Allen 102/32 3,611,939 10/1971 Stadler et al.. l02/86.5

3,685,451 8/1972 Bowring 102/70 OTHER PUBLICATIONS Military PyrotechnicsSeries; Part Three; AMCP 706-187, Oct. 1963, pp. 243-245.

Primary Examinerl-larvey E. Behrend Assistant ExaminerC. T. JordanAttorney, Agent, or Firm-Hall & Houghton [57] ABSTRACT 15 Claims, 10Drawing Figures US. Patent Oct. 14,1975 Sheet1of4 3,911,823

FIGJ.

Oct. 14, 1975 Sheet 2 of4 3,911,823

US. Patent U.S.'Patent Oct. 14,1975 Sheet30f4 3,911,823

US. Patent Oct. 14, 1975 FIG. IO.

Sheet 4 of 4 Fla. 9

PYROTECHNIC DEVICES This invention relates to pyrotechnic devices, andespecially to the ignition of such devices.

Primers are generally used for the ignition of pyrotechnic devices andthese fall into two main categories, that is to say,electrically-operated primers and mechanically-operated primers.Mechanicallyoperated primers comprise friction-operated primers andimpact-operated primers, for example, percussion primers (for example,percussion caps). For portable pyrotechnic devices, withelectrically-operated primers a source of electrical power either has tobe carried with the devices or built into them and, usually, withimpact-operated primers a striker mechanism either has to be built intothe devices or carried with them. Such a source of electrical power orsuch a striker mechanism in general occupies a significant proportion ofthe volume and weight of the respective pyrotechnic device with which itis carried or into which it is built.

The invention provides a pyrotechnic device which includes pyrotechniccomposition and a percussion primer for igniting the composition,wherein the pyrotechnic composition includes a fuel and a solidoxidising agent and the percussion primer comprises a tube, thecircumferentially-extending wall of which is deformable and an end ofwhich is open, an anvil extending lengthwise in the tube, and a mass ofprimer composition located in the tube between the anvil and thecircumferentially-extending wall of the tube.

Such primers have previously only been proposed as part of photographicflash bulbs. Their use as primers in pyrotechnic devices with a solidoxidising agent gives considerable advantages.

It is to be understood that the phase the pyrotechnic compositionincludes a fuel and a solid oxidising agent includes the case where asingle compound, for example, T.N.T., constitutes both the fuel and thesolid oxidising'agent.

To ignite the pyrotechnic device it is merely necessary for a blow so toimpinge on the tube that primer composition is compressed between thecircumferentially-extending wall of the tube and the anvil, or for thetube as a whole to be squashed, for example, to be compressed against anexternal anvil. Any tendency that the blow would have to close the tubebetween the composition and the said open end is overcome by the anvilextending lengthwise in the tube.

With a suitable choice of primer composition, the primer can be madevery sensitive. With a suitable choice of material for the wall of thetube, the primer can be operated by a less powerful blow than thatrequired to operate conventional percussion primers since little or nostretching of the wall occurs when the blow impinges on the tube. Thesetwo facts, together with the fact that, provided the primer compositionis suitably distributed, the primer will ignite if the tube is struck atany of a number of positions along its length and around itscircumference, enable a striker mechanism to be used of a much smallerand much simpler construction that that of conventional strikermechanisms for conventional percussion caps, and also be built to muchwider tolerances than conventional striker mechanisms.

Various forms of primer comprising a deformable tube and anvil extendinglengthwise in the tube and suitable for use in a pyrotechnic deviceaccording to the invention are described and claimed in PatentSpecifications referred to hereinafter.

Advantageously, the mass of primer composition is supported on theanvil; this facilitates the assembly of the primer. Preferably, the massof primer composition is spaced from the inside wall of the tube. Withsuch a construction, the primer tube is sufficiently inactive duringassembly and handling prior to its being struck to avoid prematureignition, but is nevertheless sensitive when struck in use. Preferably,the anvil has a portion of greater diameter than that of the primercomposition, the primer composition being arranged on the anvil to theside of the said portion that is nearer to the said open end of thetube. Thisassists in preventing ignition of the composition duringinsertion of the anvil into the tube in assembly of the primer.Preferably, the anvil has a further portion of greater diameter thanthat of the primer composition spaced apart in the tube from thefirst-mentioned portion, the primer composition being arranged on theanvil between the said portions. Advantageously, the anvil is supportedin the tube by engagement of the anvil, directly or indirectly, with thewalls of the tube. Thus, the anvil may comprise a wire deformed so as toabut the inside of the tube and be thereby retained. Preferably, theanvil is provided with two or more protuberances spaced apart along thelength of the anvil and in engagement with the wall of the tube. One ofthe protuberances may comprise a head portion at the end of the anvilthat is innermost in the tube, the tube being crimped to maintain thehead in position. This tends to stabilise the anvil against movementalong its length. The protuberances may comprise the said portions ofthe anvil of diameter greater than that of the primer composition.Primers possessing the above features and suitable for use inpyrotechnic devices according to the invention are described and claimedin United Kingdom Pat. Specifications Nos. 1,215,276 and 1,204,975.

Advantageously, a refractory member, preferably supported on the anvil,is supported adjacent to the said open end of the tube and lying on theaxis of the tube. Such a member deflects and spreads the stream of hotprimer particles leaving the tube when it is struck, thereforefacilitating the ignition of the pyrotechnic device. The refractorymember also enables more primer composition to be used. Primerscomprising a defonnable tube and anvil extending lengthwise in the tubewhich possess such a refractory member and are suitable for use inpyrotechnic devices according to the invention are described and claimedin United Kingdom Pat. Specification No. 1,216,056.

The tube of the primer may be open at both ends, which enables twocombustions to be initiated at the same time. instead, the opposite endof the tube to that which is open may be closed.

In order that a flame should emanate from the ends, or from the desiredend, of the tube, the tube should be made of a material which defonnsbut does not rupture to any substantial degree when the tube is struck.A small rupture of the tube caused by the impingement of the striker onthe tube may not affect the operation of the primer since the strikermay itself seal the break in the tube.

The tube is preferably of soft metal (for example, copper or so-called"No. 4 alloy," a nickel-chromium steel), and the anvil, which may be awire, is preferably of hard metal, for example, tungsten. Primers inwhich the tube and anvil are constructed of these materials, and whichare suitable for use in pyrotechnic devices according to the inventionare described and claimed in United Kingdom Pat. Specification No.1,204,973.

Advantageously, the primer composition comprises particles of apercussively ignitable material and an incandescible substance in powderform, which is such that, when the primer is struck, the ignitablematerial itself ignites and forces hot particles of the incandesciblesubstance to issue from the primer and cause ignition of the pyrotechnicdevice. The incandescible substance serves to dilute the percussivelyignitable material and provides glowing particles for communicating thecombustion. The percussively ignitable material preferably comprises amixture of phosphorus (preferably, red phosphorus) and potassiumchlorate; the weight ratio of the phosphorus to the potassium chrate ispreferably between 1:5 and 1:2. Such mixtures explode easily when theprimer is struck. The primer composition may be one of the formsdescribed and claimed in United Kingdom Pat. Specification No.1,203,857.

The incandescible substance is preferably an incandescible metal, andmay comprise zirconium, hafnium or thorium; the particle size may bewithin the range of from approximately 0.5 microns to approximately 5microns. The incandescible substance may comprise silicon. It has beenfound that this decreases the velocity of gas leaving the primer ascompared with when zirconium is used. Although this effect can also beobtained, when the incandescible metal comprises zirconium, byincreasing the relative quantity of incandescible metal in the mixture,this carries with it the disadvantage of a reduction in impactsensitivity. To give a further decrease in gas velocity and increase inimpact sensitivity, the incandescible substance may comprise boron.Preferably, the incandescible substance comprises a mixture of zirconiumand boron, which has better impact sensitivity and burningcharacteristics and gives more reliable ignition than boron alone.Suitable proportions for primer compositons incorporating silicon,boron, and zirconium and boron together are described and claimed inUnited Kingdom Pat. Specification Nos. 1,208,532, 1,203,897 and1,208,709, respectively.

Details of additives which may be incorporated in the primer compositionand of a suitable binder are described and claimed in United KingdomPatent Specification No. 1,203,857. United Kingdom Pat. SpecificationsNos. 1,207,779, 1,203,859, 1,204,974 and 1,205,090, describe and claimways in which the primer may be constructed.

Advantageously, there is provided an intermediate composition arrangedto be directly ignited by the primer and in turn arranged to ignite thepyrotechnic composition. The pyrotechnic composition may be igniteddirectly or indirectly by the intermediate composition. The intermediatecomposition may be a powdered combustible substance, for example,gunpowder. The powdered combustible substance may extend into the saidopen end of the primer tube; there may be provided a tubular member, thesaid open end of the primer tube being in close fit with the interior ofthe tubular member, and the combustible substance being contained in thetubular member. Instead, the intermediate composition may be impregnatedon a textile material; the intermediate composition may for example beformed by quickmatch or primed cambric. Instead,

the intermediate composition may be formed by a length of safety fuse.In such a case, the end of the fuse to be ignited may have a surfacelayer of powdered combustible material, for example, gunpowder.

The pyrotechnic composition may be flare-producing composition,smoke-producing composition or rocket propellant, the respective devicesbeing flares, smoke devices, or rockets. Many other types of pyrotechniccomposition can be ignited using the primer, the only restriction placedon them being that they must include a fuel and a solid oxidising agent.For example, the pyrotechnic composition may be a flash-producingcomposition (as in a thunder flash) or other light-producingcomposition. Or the pyrotechnic composition may be a gas-producingcomposition as used in oxygenproducing devices (so-called oxygencandles), a pyrotechnic composition for use in exothermic (orheatproducing) devices of the incendiary type (which may be used forwelding), an explosive composition as used in explosives or as anejection charge, or a delay train, for example, a Bickford fuse.Although it will generally be preferable to use an intermediatecomposition, the pyrotechnic composition of such pyrotechnic devices mayin certain instances be ignited directly by the hot gases from theprimer. Gunpowder, for example, could be ignited directly. Examples ofpyrotechnic devices in which such a combination of primer andintermediate composition may be employed for igniting the pyrotechnicdevice, in accordance with the invention, are described and claimed inthe Applicants United Kingdom Pat. Specifications Nos. 1,138,192,1,231,181, 1,276,085, 1,277,573, 1,275,735, 1,284,499 1,312,444,1,309,548, 1,314,811, 51563/70, 19537/71, and 15517/72, and in UnitedKingdom Pat. Specifications Nos. 929,309 and 996,872.

Alternatively, the pyrotechnic device may simply be an igniter, in whichcase the said pyrotechnic composition is an intermediate composition forigniting a further pyrotechnic device, the intermediate compositionbeing arranged to be directly ignited by the primer. Such intermediatecomposition could be any of the forms of intermediate compositionreferred to hereinbefore. Such an igniter could be simply inserted, forexample, into a suitably-designed smoke-producing, flare-producing orrocket device when it was desired to fire it.

It should be noted that either of the two basic forms of primerdescribed hereinbefore, that is, the deformable tube and lengthwiseanvil form and the cup-shaped member and flat-faced anvil form, can beused in the pyrotechnic devices described.

The pyrotechnic device may include a length of resilient wire forstriking the primer, the wire being so arranged that, when retracted andreleased, it strikes the primer tube transversly. Such an arrangementmay be used for igniting a pyrotechnic device underwater, since thefrictional drag on the wire would be relatively small. Alternatively,the device may include a cocked spring-loaded striker. The striker maybe retained in a cocked position by the body housing the primer tube,and permitted to enter an aperture in a body housing the primer tube onrelative movement between the body and the striker.

An advantage of the form of primer comprising the deformable tube isthat, with many forms of striker mechanism, it will be possible tooperate the device even if the striker mechanism fails to operate simplyby tapping the primer tube with a suitable implement, for example, apencil.

Pyrotechnic devices constructed in accordance with the invention willnow be described, by way of example, with reference to the accompanyingdrawings, in which:

FIG. 1 is a plan view of an igniter;

FIG. 2 is an axial cross-section of the igniter;

FIG. 3 is a section through the plane 33 in FIG. 2;

FIG. 4 is an enlarged view of the primer tube of the device;

FIG. 5 is an axial view, partly in section, of a linethrowerincorporating the igniter of FIGS. 1 to 4;

FIG. 6 is an axial cross-section of a further igniter;

FIG. 7 is an axial cross-section of a further igniter;

FIG. 8 is an axial cross-section of a smoke grenade incorporating theigniter of FIG. 7;

FIG. 9 is an axial cross-section of a rocket incorporating the igniterof FIG. 6; and

FIG. 10 is an axial cross-section of a hand-flare incorporating anigniter similar to that of FIGS. 1 to 4.

Like parts are given like reference numerals in all the Figures.

The igniter of FIGS. 1 to 4 may be used for igniting and ejecting arocket from a discharge tube. The igniter may, for example, be insertedin the lower end of a discharge tube of suitable dimensions.

Referring to FIGS. 1 to 4, the device comprisesa tubular primer,indicated generally by the reference numeral 1, a mass of intermediatecomposition 2 and an ejection charge 3. These are housed in an assemblycomprising a base portion of plastics material indicated generally bythe reference numeral 4 and a hollow tubular portion 5 of plasticsmaterial. The ejection charge 3 is held in position by a bursting disc 6in turn held in position by a circlip 7.

Referring to FIG. 4, the primer comprises a tube 8 of copper and ananvil 9 which extends lengthwise in the tube and co-axially with respectto the tube 8, and which is formed of tungsten. One end of the tube 8 isclosed.

The anvil 9 carries a mass of primer composition 12 which may have thefollowing composition, the parts being by weight on a dried basis:powdered boron, 21.23%; powdered zirconium, 19.59%, red phosphorus,28.71%; potassium chlorate, 28.71%; hydroxyethyl cellulose, 1.74%; andortho-phenyl-phenol, 0.01%. Water is added to give a primer compositionof a viscosity facilitating its application to the anvil 9.

The anvil 9 is supported in the tube 8 by means of protuberances l0 and11. The protuberance 11 is formed as a head on the anvil and is adjacentto the closed end of the tube 8. The tube 8 is crimped around it tostabilise the anvil 9 against movement along its length. Theprotuberance 10 comprises four equally spaced apart circular vanes whichengage the inner wall of the tube. The primer composition 12 is spacedapart from the wall of the tube. The diameter of the protuberances 10and 11 is greater than that of the mass of composition 12 so as toassist in preventing contact with the wall of the tube 8 as the anvil 9is being inserted into the tube and hence assist in preventing ignitionof the composition 12.

A refractory bead 13 is supported on the anvil 9 adjacent to the openend of the tube for deflecting the stream of gases issuing from the tubewhen the primer is struck.

As an example of suitable dimensions for the primer 1, the primer tube 8may be about 8 mm. long and about 1 /2 mm. in diameter, and the overalllength of the primer about 14 mm.

The primer 1 is maintained in position in the assembly'by means of acirclip 14 which engages a groove in the inner'wall of a cup-shapedmember 15 which is in turn secured in an aperture in the base portion 4.The flared wall of the open end of the primer tube 8 engages the wall ofthe adjacent end portion of the bore in the tubular portion 5 and alsoassists in maintaining the primer in position. Alternatively, the primermay be in a light push-fit in a recess in the assembly, and/or may besecured in position by adhesive.

The base portion 4 has an annular extension 16, a part of which is cutaway to define a slot between the base portion and the tubular portion 5which receives a striker plate 17. The striker plate 17 is slidable inthe direction of the arrow 18. A spring indicated generally by thereference numeral 19 is secured to the tubular portion 5 at 19a andextends around a post 20 secured to the tubular portion. A turned-overportion 21 of the striker plate 17 retains an arm 22 of the spring 19.The spring 19 urges the plate 17 against the inner wall of the annularextension 16, and the relative dimensions of the parts are such that thearm 22 is clear of the primer tube.

The device is assembled by placing the circlip 14 on the primer tube andinserting it into the cup-shaped member 15. The base portion is thensecured to the tubular portion (the spring and plate having beeninserted), and finally the cup-shaped member 15 is inserted into theaperture in the base portion and secured in position.

The intermediate composition 2 may be FFF gunpowder (marketed by ICILimited), the grains of which are nominally of sizes such as to pass a24 mesh sieve and be retained on a mesh sieve (B.S.S. 410) and which hasthe following composition, the parts being by weight:

Potassium nitrate parts Sulphur 10 parts Charcoal 15 parts The ejectioncharge 3 may be a coarser gunpowder, for example, T.P. Cannon (marketedby [C1 Limited), the grains of which are nominally of sizes such as topass an 8 mesh sieve and to be retained on a 20 mesh sieve (B.S.S. 410)and which has the same composition as given above for the ignitercomposition. In each case, the potassium nitrate constitutes the solidoxidising agent.

In operation, the striker plate 17 is moved in the direction of thearrow 18 until the arm 22 of the spring 19 slides out of the turned-overportion 21 of the plate 17. The arm 22 then strikes the primer tube 1,the primer tube being so positioned that it does so in the region of theprimer composition 12. This deforms the circumferentially-extending wallof the tube 8 and compresses the primer composition 12 between the anvil9 and the circumferentially-extending wall of the tube 8 therebyigniting the primer composition. The flame from the primer composition12 ignites the intermediate composition 2 which in turn ignites theejection charge 3. With the assembly suitably positioned in a dischargetube, the flame from the ejection charge ignites and ejects the rocketfrom the discharge tube.

Referring to FIG. 5, the igniter of FIGS. 1 to 4 may be used forigniting and firing a line-throwing rocket. The igniter is secured, bymeans of pegs 23, in a bayonet-fitting socket in the lower end of a tube24, which is itself secured to the lower end of a discharge tube 25. Thetube 24 opens into the lower end of the discharge tube 25.

The igniter is operated by means of a trigger 26, which is guided inapertures in the outer case 27 of the line-throwing rocket and in aprotective casing 28 which houses the igniter unit. One end portion ofthe trigger 26 is bent at right angles and extendss in the opening inthe striker plate 17, and the other end portion of the trigger 26 isformed in a loop.

A rocket 29 has a bridle 30 secured to its upper end, and the rocket 29rests in the discharge tube by means of a band 31 surrounding therocket.

The bridle is connected by means of a heat resisting connection portion32 to a coil of line 33 housed in a tubular container 34.

In operation, the device is held by means of a handle 35 and, afterremoval of an upper closure 36, the device is operated by retracting theend of the trigger 26 that is formed in a loop. This causes the igniterto operate in the manner described with reference to FIGS. 1 to 4, andthe rocket 29 is both ignited and ejected from the discharge tube 25 bythe explosion of the gunpowder 3.

Referring to FIG. 6, the igniter shown is identical to that shown inFIGS. 1 to 4 as far as the construction, arrangement and composition ofthe primer 1 and the striker mechanism is concerned. The igniter of FIG.6 differs from that shown in FIGS. 1 to 4 in that the primer ignites anintermediate composition impregnated on a textile material, rather thanan intermediate composition in the form of a powdered combustiblematerial as in FIGS. 1 to 4.

The tubular portion 5 of FIG. 2 is considerably shorter in the igniterof FIG. 6 and terminates in a neck 37 having a lip 38. A ferrule 39 issecured to the neck 37 by means of a hollow cup 40 which is crimped atthe edge 41.

The ferrule holds a strand 42 of quickmatch, the end of which is exposedto the open end of the primer tube 8.

In operation, the striker plate 17 is moved in the same direction as inthe striker of FIGS. 1 to 4 until the spring is released ans strikes theprimer 1. The flame from the primer 1 ignites the quickmatch 2, whichmay then itself ignite a suitable pyrotechnic devices. The striker plate17 is secured by means of a ring 43 to a length of cord 44, and thestriker plate 17 may be withdrawn by means of the cord 44.

Referring to FIG. 7, the igniter shown is again similar to that shown inFIGS. 1 to 4 in the construction, arrangement, and composition of theprimer 1, and in the construction and operation of the strikermechanism. In this igniter, however, the primer 1 ignites anintermediate composition which is formed by the central train ofgunpowder of a Bickford or safety fuse 45.

The tubular member 5 is modified in the same way as in FIG. 6 toterminate in the neck 37 bearing a lip 38. A ferrule 46 is secured tothe neck 37 by means of a hollow cup 40 which is crimped around thelower edge of the lip 38. The ferrule 46 is provided with two ventapertures 47.

In order to facilitate ignition of the Bickford fuse, the end of thefuse that is exposed to the primer 1 has a surface layer of combustiblematerial in hte form of mealed gunpowder. The Bickford fuse may be dry(for example by a dusting treatment) or wet (for example by means of aslurry in gum arabic and water) primed with the gunpowder.

In operation, the striker plate 17 is withdrawn (by means of a cord 44if desired) until the arm 22 of the spring 19 is released, an strikesthe primer 1. The flame from the primer ignites the Bickford fuse, whichmay then be used to itself ignite a suitable pyrotechnic device.

FIG. 8 shows an example of the way in which the igniter of FIG. 7 may beused, the igniter being used in a smoke grenade.

The smoke grenade has an aluminum outer casing 48 which contains smokeproducing composition 49 in its lower part, and a smoke baffle in itsupper part. The casing 48 is protected from the smoke producingcomposition 49 by means of a tubular sleeve 50 and a thick disc 51. Thesmoke baffle is formed by a perforated tin plate disc 52, anintermediate perforated disc 53 and an upper perforated disc 54, thediscs 52 and 53, and 53 and 54, being spaced apart by collars 55 and 56,respectively. The upper end of the aluminum case 48 is turned on to aretaining collar 57 to hold the contents of the smoke grenade inposition.

The upper surface of the smoke producing composition 49 has a layer ofigniter composition 58, and this layer of igniter composition is in turncovered by an annular primed cambric disc 59, which is held in positionby the baffle disc 52. Rolls of primed cambric 60 and 61 are alsoincluded to promote rapid ignition of the smoke producing composition49.

The igniter extends into a central bore in the smoke producingcomposition 49, and the upper part of the bore is of larger diameter andlined with a perforated aluminum sleeve 62 to facilitate ignition of thegrenade.

The igniter is that shown in FIG. 7. In addition, a capsule 62acontaining gunpowder (or equivalent) is pushed over, and secured to, thelower end of the Bickford fuse 45. The body of the igniter is held in acentral aperture in the perforated tin plate disc 52, and the igniter isoperated by pulling the cord 44 which is secured to a ring 63. The cord44 is run through the eyelets 64 secured to the collars 55 and 56, andpasses through apertures in the discs 53 and 54. The ring 63 is securedto the disc 54 by means of a tear-off strip (not shown) which closes theapertures in the disc 54.

As an example of a suitable smoke-producing composition, thesmoke-producing composition may be as follows:

Potassium chlorate Lactose or Sucrose Dyestuff 25 parts by weight 25parts by weight 50 parts by weight In operation, the tear-off strip isremoved to release the ring 63, and the ring 63 is then pulled away fromthe smoke grenade. The striker plate 17 is retracted in the samedirection as FIG. 7, and the Bickford fuse 45 is ignited as describedwith reference to FIG. 7. (Immediately after pulling the cord 63, thedevice is thrown by the user.) This ignites the gunpowder capsule 62awhich in turn ignites the primed cambric roll 61 and, because of thesleeve 62, the primed cambric disc 59. The smoke producing composition49 is thus ignited rapidly.

If desired, the igniters of FIG. 6 and FIGS. 1 to 4 (with the possibleelimination of the ejection charge 3) could be used in a smoke grenadeof FIG. 8. Also, the igniters could be used to ignite smoke producingcomposition in other types of device, for example, in hand held smokesignals, buoyant smoke signals, smoke markers for marking positions onthe ground, or pesticides.

FIG. 9 shows the igniter of FIG. 6 used to ignite a rocket indicatedgenerally by the reference numeral 65. The rocket 65 comprises an outercasing 66 and a motor casing 67, which houses the rocket propellant 68and a nozzle 69. The nozzle 69 has an annular recess containing ignitersubstance, suitable forms of which are described in British Pat.Specification No. 1,138,192, to facilitate ignition of the propellant68. The rocket is housed in a discharge tube 70, the upper and lowerends of which are covered by push fit closures 71 and 72, respectively.

The igniter of FIG. 6 is supported in a disc 73 which closes the lowerend of the discharge tube 70. The quickmatch strand 42 extends from theigniter through the nozzle aperture of the rocket to the region adjacentthe propellant 68. The quickmatch is supported by a plastic or rolledpaper tube 74 between the igniter and the nozzle aperture, and the upperend of the quickmatch is bent over.

The cord 44 extends through an eyelet 75 to a ring 76.

As an example of a suitable propellant, the following composition may beemployed, the percentages being by weight,

Ammonium perchlorate 84.5% Polyisobutene 12.5% Surface-active agent 1%(Pentaerthritol dioleate 30% Ehtyl oleate 40% Sodium dioctylsulphosuccinate 30% Copper chromate 2% The ammonium perchlorateconstitues the solid oxidising agent.

ln operation, both the upper and lower closures 71 and 72, respectively,areremoved, and the ring 76 is pulled away from the discharge tube 70.The igniter is operated as described with reference to FIG. 6, and therocket propellant 68 is ignited by means of the quickmatch 42, so thatthe rocket leaves the discharge tube 70.

If desired the igniter of FIG. 7 could be used in FIG. 9, for example,by using a length of quickmatch to lgnite the rocket that was ignited bythe fuse 45.

FIG. shows a hand flare which incorporates an igniter similar to that ofFIGS. 1 to 4. The flare comprises an outer casing 77, a mass of flarecomposition 78 contained therein and protected from the wall of thecasing 77 by an inhibiting layer 79. The lower end of the casing 77 isused as a handle for the device.

A layer of clay 80 covers the lower surface of the flare composition,and the upper surface is gunpowderprimed.

The igniter is identical to that shown in FIGS. 1 to 4 except that theejection charge 3, the bursting disc and the circlip 7 are omitted, andthe intermediate composition 2 is held in by means of a paper disclocated at the inner end of the portion of the bore in the tubularmember 5 that is of greatest diameter. The body of the igniter is heldin the casing 79 by means of a spider 81. The cord 44 is secured via aneyelet 82 to a ring 83. The upper end of the casing 77 is a removableclosure 84.

As an example of a suitable flare composition, the following may beemployed, the parts being by weight Magnesium 35 Boiled Linseed Oil 4Potassium Perchlorate 30 Strontium Carbonate l l Chlorinated Rubber 20This will produce a red flare. The potassium perchlorate constitutes thesolid oxidising agent.

In operation, the closure 78 is removed and the ring 83 is pulled tooperate the igniter. The flame from the intermediate composition 2ignites the flare composition 78.

If desired, the igniters of FIGS. 6 or 7 could be used in place of thatshown in FIG. 10. Also, the igniters could be used to ignite flarecomposition other than in a hand flare. For example, the flarecomposition could be in a device designed to be released from underwateror in a buoyant device to be thrown into water, or a parachute flareused for reconnaissance.

We claim:

1. A pyrotechnic device which includes pyrotechnic composition and apercussion primer located therein for igniting said composition, whereinsaid pyrotechnic composition includes a fuel and a solid oxidising agentand said percussion primer is a photoflash-lamp-type primer comprising atube having a wall deformable by striking the same, a rod-like anvilextending lengthwise in said tube, and a mass of sensitive primercomposition supported on said anvil and spaced apart from the insidesurface of said wall, said primer composition ineluding phosphorus andachlorate salt.

2. A pyrotechnic device which includes pyrotechnic composition and apercussion primer located therein for igniting said composition, whereinsaid pyrotechnic composition includes a fuel and a solid oxidising agentand said percussion primer is a photoflash-lamp-type primer comprising atube having a wall deformable by striking the same, a rod-like anvilextending lengthwise in said tube, and a mass of sensitive primercomposition supported on said anvil and spaced apart from the insidesurface of said wall, said primer composition comprising particles of apercussively ignitable material and an incandescible substance in powderform, whereby, when said primer is struck, said ignitable materialitself ignites and forces hot particles of said incandescible substanceto issue from said primer to ignite said pyrotechnic device.

3. A pyrotechnic device according to claim 2, wherein said percussivelyignitable material includes phosphorus and a chlorate salt.

4. A device according to claim 3, wherein said device further includes atubular member, an open end of said primer tube being in close fit withthe interior of said tubular member, powdered combustible substancecontained in said tubular member, and a retainer to retain saidcombustible substance within said tubular member.

5. A device according to claim 3, including a quickmatch strand, andmeans to retain said quickmatch strand in the region of an open end ofsaid primer tube.

6. A device according to claim 3, including a length of safety fuse,means to retain an end of said length of safety fuse in the region of anopen end of said primer tube, said end of said safety fuse having asurface layer of powdered combustible material.

7. A device according to claim 3, including a length of resilient wire,said wire being positioned for transverse striking of said primer tube,whereby, when said wire is retracted and released, it strikes saidprimer tube transversly.

8. A device according to claim 3, wherein said primer tube has oneclosed end.

9. A device according to claim 8, wherein said primer tube is of softmetal and said anvil is of hard metal.

10. A device according to claim 9, including a refractory member, saidrefractory member being supported on said anvil adjacent said open endof said tube and lying on the axis of said tube, and having a greaterdiameter than the anvil in a plane perpendicular to the axis of theanvil.

11. A device according to claim 10, wherein said percussively ignitablematerial includes red phosphorus and potassium chlorate in a weightratio of said phosphorus to said potassium chlorate of between 1:5 and1:2.

12. A flare-producing device which includes flareproducing compositionand a percussion primer located therein for igniting said composition,wherein said flare-producing composition includes a fuel and a solidoxidising agent and said percussion primer is a photoflash-lamp-typeprimer comprising a tube having a wall deformable by striking the same,a rod-like anvil extending lengthwise in said tube, and a mass ofsensitive primer composition supported on said anvil and spaced apartfrom the inside surface of said wall, said primer composition comprisingparticles of a percussively ignitable material and an incandesciblesubstance in powder form, said percussively ignitable material includingphosphorus and a chlorate salt, whereby, when said primer is struck,said ignitable material itself ignites and forces hot particles of saidincandescible substance to issue form said primer to ignite saidflare-producing device.

13. A smoke-producing device which includes smoke-producing compositionand a percussion primer located therein for igniting said composition,wherein said smoke-producing composition includes a fuel and a solidoxidising agent and said percussion primer is a photoflash-lamp-typeprimer comprising a tube having a wall deformable by striking the same,a rod-like anvil extending lengthwise in said tube, and a mass ofsensitive primer composition supported on said anvil and spaced apartfrom the inside surface of said wall, said primer composition comprisingparticles of a percussively ignitable material and an incandesciblesubstance in powder form, said percussively ignitable material includingphosphorus and a chlorate salt, whereby, when said primer is struck,said ignitable material itself ignites and forces hot particles of saidincandescible substance to issue from said primer to ignite saidsmoke-producing device.

14. A rocket which includes rocket propellant and a percussion primerlocated therein for igniting said propellant, wherein said propellantincludes a fuel and a solid oxidising agent and said percussion primeris a photoflash-lamp-type primer comprising a tube having a walldeformable by striking the same, a rod-like anvil extending lengthwisein said tube, and a mass of sensitive primer composition supported onsaid anvil and spaced apart from the inside surface of said wall, saidprimer composition comprising particles of a percussively ignitablematerial and an incandescible substance in powder form, saidpercussively ignitable material including phosphorus and a chloratesalt, whereby, when said primer is struck, said ignitable materialitself ignites and forces hot particles of said incandescible substanceto issue from said primer to ignite said rocket.

15. An igniter unit comprising a body portion adapted to be received inthe ignition chamber of a device, intermediate composition contained insaid body portion and a percussion primer secured to said body portionfor igniting said composition, wherein said interniediate compositionincludes a fuel and a solid oxidising agent and said percussion primeris a photoflashlamp-type primer comprising a tube having a walldeformable by striking the same, a rod-like anvil extending lengthwisein said tube, and a mass of sensitive primer composition supported onsaid anvil and spaced apart from the inside surface of said wall, saidprimer composition comprising particles of a percussively ignitablematerial and an incandescible substance in powder form, saidpercussively ignitable material including phosphorus and a chloratesalt, whereby, when said primer is struck, said ignitable materialitself ignites and forces hot particles of said incandescible substanceto issue from said primer to ignite said intermediate composition.

1. A pyrotechnic device which includes pyrotechnic composition and apercussion primer located therein for igniting said composition, whereinsaid pyrotechnic composition includes a fuel and a solid oxidising agentand said percussion primer is a photoflash-lamp-type primer comprising atube having a wall deformable by striking the same, a rod-like anvilextending lengthwise in said tube, and a mass of sensitive primercomposition supported on said anvil and spaced apart from the insidesurface of said wall, said primer composition including phosphorus and achlorate salt.
 2. A pyrotechnic device which includes pyrotechniccomposition and a percussion primer located therein for igniting saidcomposition, wherein said pyrotechnic composition includes a fuel and asolid oxidising agent and said percussion primer is aphotoflash-lamp-type primer comprising a tube having a wall deformableby striking the same, a rod-like anvil extending lengthwise in saidtube, and a mass of sensitive primer composition supported on said anviland spaced apart from the inside surface of said wall, said primercomposition comprising particles of a percussively ignitable materialand an incandescible substance in powder form, whereby, when said primeris struck, said ignitable material itself ignites and forces hotparticles of said incandescible substance to issue from said primer toignite said pyrotechnic device.
 3. A pyrotechnic device according toclaim 2, wherein said percussively ignitable material includesphosphorus and a chlorate salt.
 4. A device according to claim 3,wherein said device further includes a tubular member, an open end ofsaid primer tube being in close fit with the interior of said tubularmember, powdered combustible substance contained in said tubular member,and a retainer to retain said combustible substance within said tubularmember.
 5. A device according to claim 3, including a quickmatch strand,and means to retain said quickmatch strand in the region of an open endof said primer tube.
 6. A device according to claim 3, including alength of safety fuse, means to retain an end of said length of safetyfuse in the region of an open end of said primer tube, said end of saidsafety fuse having a surface layer of powdered combustible material. 7.A device according to claim 3, including a length of resilient wire,said wire being positioned for transverse striking of said primer tube,whereby, when said wire is retracted and released, it strikes saidprimer tube transversly.
 8. A device according to claim 3, wherein saidprimer tube has one closed end.
 9. A device according to claim 8,wherein said primer tube is of soft metal and said anvil is of hardmetal.
 10. A device according to claim 9, including a refractory meMber,said refractory member being supported on said anvil adjacent said openend of said tube and lying on the axis of said tube, and having agreater diameter than the anvil in a plane perpendicular to the axis ofthe anvil.
 11. A device according to claim 10, wherein said percussivelyignitable material includes red phosphorus and potassium chlorate in aweight ratio of said phosphorus to said potassium chlorate of between1:5 and 1:2.
 12. A flare-producing device which includes flare-producingcomposition and a percussion primer located therein for igniting saidcomposition, wherein said flare-producing composition includes a fueland a solid oxidising agent and said percussion primer is aphotoflash-lamp-type primer comprising a tube having a wall deformableby striking the same, a rod-like anvil extending lengthwise in saidtube, and a mass of sensitive primer composition supported on said anviland spaced apart from the inside surface of said wall, said primercomposition comprising particles of a percussively ignitable materialand an incandescible substance in powder form, said percussivelyignitable material including phosphorus and a chlorate salt, whereby,when said primer is struck, said ignitable material itself ignites andforces hot particles of said incandescible substance to issue form saidprimer to ignite said flare-producing device.
 13. A smoke-producingdevice which includes smoke-producing composition and a percussionprimer located therein for igniting said composition, wherein saidsmoke-producing composition includes a fuel and a solid oxidising agentand said percussion primer is a photoflash-lamp-type primer comprising atube having a wall deformable by striking the same, a rod-like anvilextending lengthwise in said tube, and a mass of sensitive primercomposition supported on said anvil and spaced apart from the insidesurface of said wall, said primer composition comprising particles of apercussively ignitable material and an incandescible substance in powderform, said percussively ignitable material including phosphorus and achlorate salt, whereby, when said primer is struck, said ignitablematerial itself ignites and forces hot particles of said incandesciblesubstance to issue from said primer to ignite said smoke-producingdevice.
 14. A rocket which includes rocket propellant and a percussionprimer located therein for igniting said propellant, wherein saidpropellant includes a fuel and a solid oxidising agent and saidpercussion primer is a photoflash-lamp-type primer comprising a tubehaving a wall deformable by striking the same, a rod-like anvilextending lengthwise in said tube, and a mass of sensitive primercomposition supported on said anvil and spaced apart from the insidesurface of said wall, said primer composition comprising particles of apercussively ignitable material and an incandescible substance in powderform, said percussively ignitable material including phosphorus and achlorate salt, whereby, when said primer is struck, said ignitablematerial itself ignites and forces hot particles of said incandesciblesubstance to issue from said primer to ignite said rocket.
 15. Anigniter unit comprising a body portion adapted to be received in theignition chamber of a device, intermediate composition contained in saidbody portion and a percussion primer secured to said body portion forigniting said composition, wherein said intermediate compositionincludes a fuel and a solid oxidising agent and said percussion primeris a photoflash-lamp-type primer comprising a tube having a walldeformable by striking the same, a rod-like anvil extending lengthwisein said tube, and a mass of sensitive primer composition supported onsaid anvil and spaced apart from the inside surface of said wall, saidprimer composition comprising particles of a percussively ignitablematerial and an incandescible substance in powder form, saidpercussively ignitable material including phosphorus and a chloratesalt, whereby, when sAid primer is struck, said ignitable materialitself ignites and forces hot particles of said incandescible substanceto issue from said primer to ignite said intermediate composition.